This invention relates to a method of storing set-up data for a photo-electric scanner in the form of graphs and an apparatus for reading such graphs for use as set-up data.
In operating photo-electric scanners, it is preferable to have desired set-up data in an easily accessible manner so that any particular set of set-up data can be quickly set up on the photo-electric scanners which operate on a real-time basis. To that end, it is necessary to store a wide variation of set-up data in computer memories in the form of tables with proper indices for the convenience of selective retrieval.
Normally, storage of such tables in memory devices are made by controlling the memory devices using a central processing unit (CPU).
In such cases, a table is made from a characteristic curve drawn in a graph which corresponds to the characteristics of color correction, density correction or gradation correction so that the values corresponding to the input are related to the values corresponding to the output, normally by reading the output values with respect to selected input values and writing them into a memory device using a keyboard or other manual means. The input values are used as address signals which designate the data which correspond to the output values. However, such manual processes tend to be time-consuming and inaccurate.
It is possible to use a digitizer or other coordinate reading devices for reading such characteristics conversion graphs and to enter data thus derived directily into a CPU, but the high cost of such devices makes this method impractical for most applications.
As a method of storing a number of conversion tables in an easily accessible manner, it is natured to attach certain index to each set of set-up data or conversion tables. But, since the index itself has no bearing on the characteristics of the particular conversion table, it is not possible to visually inspect the characteristics of the table.
An another alternative, it is possible to store each conversion table in magnetic tape or perforated tape but, as in the previous case, the conversion characteristics recorded in the tape can not be visually compared with another table which was used in connection with another original picture.
Furthermore, if some modification is desired to be made on a conversion table, the information concerning the desired modification must be manually entered on a keyboard or the lime and it requires time-consuming work, often involvihg certain inaccuracy.